Part of the question which arises in the discussion over Paul's mention
of delivering someone to Satan in 1 Cor 5:5 is whether this is an action
taken by the church or by Paul's apostolic authority. Whatever the
action might be, is it something that can be performed today (if we no
longer have apostles)? In v. 4, I wonder if there might not be two
grammatical clues:

2) Is the SUNACQENTWN . . . SUN . . . construction a possible indicator
that the gathering together is between hUMIN KAI TOU EMOU PNEUMATOS and
TH DUNAMEI TOU KURIOU (rather than two separate ideas: the gathering of
the Corinthians with Paul's spirit, and Paul's own connection to the
power of the Lord)? I understand that SUNAGW is a common enough word
that it takes on its own distinctive meaning, but I'm simply suggesting
that Paul was using the prefixed preposition in his construction. For
comparison, see Col 2:13. It makes sense to me that SUN would be the
better point of connection than KAI.